Generally, a conventional autonomous mobile cleaner is carried to move by a plurality of common wheels, driven to rotate by a motor. Therefore, the conventional autonomous mobile cleaner can be driven to turn by the rotational speed difference between those wheels as the operating cleaner is running into obstacles like a wall or a drop of stairs. It is known that the turning of a conventional autonomous mobile cleaner carried by common wheels can be achieved in the following fashions:                (1) As the platform of the conventional autonomous mobile cleaner is moved to a specific location and stopped completely, the wheels are driven to turn toward a random direction while not rotating, and then are driven to rotate after the turn is complete. It is noted that, to turn a cease-rotating wheel, a comparatively larger friction must be overcame, not to mention that the aforesaid stop-turn-rotate fashion is time consuming. Therefore, the aforesaid turning fashion will adversely affect the moving efficiency of the autonomous mobile cleaner.        (2) As the platform is approaching a specific location, the rotating wheel is driven to turn when the platform is still in motion. It is noted that, to enable the platform to negotiate a turn while it is still in motion, the motor control will be much complicated and the resulting turn radius will be larger. Therefore, the aforesaid turning fashion will cause the autonomous mobile cleaner to have blind spot for cleaning.Hence, as the common wheel can not instantly turn and move in a random direction, the moving efficiency as well as the agility of the conventional autonomous mobile cleaner are insufficient and unsatisfactory.        
Please refer to FIG. 1, which shows a self-traveling type vacuum cleaner disclosed in JP Pat. No. 4221524. The self-traveling type vacuum cleaner 10 of FIG. 1 employs two driving wheels 12 and a passive wheel as the moving mechanism for carrying the platform 11 to move, wherein the two driving wheels 12 are driven to rotate respectively by the two independent motors 14. It is noted that the moving mechanism of the vacuum cleaner 10 is the most popular among conventional autonomous mobile cleaners. As the operating vacuum cleaner 10 is running into an obstacle, the two motors 14 are controlled to cause the generating of a speed difference between the two rotating driving wheels 12 for enabling the platform 11 to turn accordingly. As the platform 11 is turning, the passive wheel 13 will follow. However, the abovementioned moving mechanism still suffer from the comparatively larger friction while turning, and it is still not able to turn and move in a random direction instantly at will. Therefore, the mobility of the abovementioned vacuum cleaner 10 is not preferred.
Please refer to FIG. 2, which shows a spherical wheel vehicle disclosed in JP Pat. No. 2003305671. The spherical wheel vehicle 20 of FIG. 2 employs more than two spherical driving wheels 22 as the moving mechanism for carrying the platform 21 to move omni-directionally. By the aforesaid moving mechanism, even if colliding with an obstruction, it is safe because a wheel body of each spherical driving wheel 22 merely turns inside the wheel shell thereof, and a proceeding direction can be easily changed. However, since the forgoing spherical driving wheels 22 can not be driven to rotate directly by motors, a power transmission mechanism is required for transmitting power from the motors to each spherical driving wheels 22, by <which each spherical driving wheel 22 is driven to rotate by friction. Therefore, some power can be lost when the power transmission mechanism slips and thus the motion accuracy of the spherical wheel vehicle 20 can be adversely affected, not to mention that the overall driving mechanism of the spherical wheel vehicle 20 will be much more complicated.